# std::basic_streambuf<CharT,Traits>::pbump

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< cpp‎ | io‎ | basic streambuf

protected: void pbump( int count ); |  |

Repositions the put pointer (pptr()) by count characters, where count may be positive or negative. No checks are done for moving the pointer outside the put area `[`pbase()`,` epptr()`)`.

If the pointer is advanced and then overflow() is called to flush the put area to the associated character sequence, the effect is that extra count characters with undefined values are output.

### Parameters

count | - | number to add to the put pointer

### Return value

(none)

### Notes

Because this function takes an int, it cannot manipulate buffers larger than std::numeric_limits<int>::max() characters (LWG issue 255).

### Example

Run this code

    #include <fstream>
    #include <iostream>
    #include <string>

    struct showput_streambuf : std::filebuf
    {
        using std::filebuf::pbump; // expose protected
        std::string showput() const
        {
            return std::string(pbase(), pptr());
        }
    };

    int main()
    {
        showput_streambuf mybuf;
        mybuf.open("test.txt", std::ios_base::out);
        std::ostream str(&mybuf);
        str << "This is a test" << std::flush << "1234";
        std::cout << "The put area contains: " << mybuf.showput() << '\n';
        mybuf.pbump(10);
        std::cout << "after pbump(10), it contains " << mybuf.showput() << '\n';
    }

Output:

    The put area contains: 1234
    after pbump(10), it contains 1234 is a test

### See also

gbump | advances the next pointer in the input sequence (protected member function)

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